package com.itheima.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.common.BaseContext;
import com.itheima.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 *
 * @WebFilter
 * @WebFilter("过滤名称","拦截路径")
 * 用于将一个类声明为过滤器,该注解将会在部署时被容器处理,容器将根据具体的属性配置将相应的类部署为过滤器
 *
 * @Slf4j
 * 日志
 */

@WebFilter(filterName = "loginCheckFilter",urlPatterns ="/*" )//启动类加上@ServletComponentScan注解
@Slf4j
public class LoginCheckFilter implements Filter {
    //路径匹配器,支持通配符  可以用 '/**'
    public static final AntPathMatcher PATH_MATCHER =new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //将servletRequest 转成 HttpServletRequest，方便获取session
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //1、获取本次请求的URI    getRequestURI():获取URI(统一资源标识符)
        String requestURI = request.getRequestURI();// /backend/index.html
        //日志输出 查看本次请求路径   {}:表示占位符  动态输出的时候就会把后面的参数 输出到当前位置
        log.info("拦截到请求：{}",requestURI);

        //定义不需要处理的请求路径   白名单
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**",
                "/common/**",
                "/user/sendMsg",
                "/user/login"
        };
        //2、判断本次请求是否需要处理
//        boolean check = check(urls,requestURI);
        boolean check = check(urls,requestURI);

        //3、如果不需要处理，则直接放行
        if (check){
            log.info("本次请求{}不需要处理",requestURI);
            // doFilter 放行
            filterChain.doFilter(request,response);
            return;
        }

        //4-1、判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee")!=null){

            log.info("用户已登录,用户id为:{}",request.getSession().getAttribute("employee"));

            //获取当前登录用户id  从 Session 中获取
            Long empId = (Long) request.getSession().getAttribute("employee");
            //调用BaseContext 设置id
            BaseContext.setCurrentId(empId);

            //放行   doFilter:放行
            filterChain.doFilter(request,response);


            // delCurrentId:删除
             BaseContext.delCurrentId();

            //查看线程id 日志记录
            long id =Thread.currentThread().getId();
            log.info("线程id为: {}",id);
            return;
        }

        //4-2、判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("user") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));

            Long userId = (Long) request.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);

            filterChain.doFilter(request,response);
            return;
        }



        log.info("用户未登录");
        //5、如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
        //response.getWriter().write() : 设置响应体   数据类型为 json  返回 NOTLOGIN 必须和前端对应
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }


    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls){
            boolean match = PATH_MATCHER.match(url,requestURI);
            if (match){
                return true;
            }
        }
        return false;
    }


}
